Astronomers have discovered a very young and unusual-looking star – and named it Dracula’s Chivito, after a popular Uruguayan sandwich. The name is a nod to the most similar object we’ve seen before, the equally memorable Gomez’ Hamburger.
Stars can last for billions of years, but are most interesting in the relatively brief times when they are being born and dying, partly because there seems to be more diversity in those stages than in midlife. One particularly valued example is IRAS 18059-3211, discovered in 1985 from photos by Arturo Gómez. It’s been named Gomez’s Hamburger, or GoHam, because it looks like meat in a bun.
GoHam is interesting because we’re seeing it during the period when the surrounding disk has yet to condense into planets, as well as unusually edge on. At 800 light years away, it’s hardly close (although some estimates are higher), but certainly more convenient for study than most of the galaxy. Intriguingly, it’s not in a region forming other stars, unlike the vast majority of stellar newborns that tend to be closely clumped.
It’s taken 39 years from GoHam’s discovery for us to find a counterpart, but now we have an exceptionally close match. In the intervening time, the authors of a preprint paper announcing it note there has been recognition that these edge-on disks may help us answer questions raised by those we can see from other angles.
“The shadows cast by the midplane concentration of dust and gas in highly inclined disks allow direct observations of scattered light from the central star, unveiling the vertical distribution of dust particles, providing information about their sizes, compositions, and settling mechanisms,” they note.
The team was not looking for GoHam’s siblings when they made their discovery, searching instead for galaxies that might have black holes feeding on infalling material. In the process, they came upon an object whose disk they say; “Has the characteristic bipolar appearance of edge-on disks with the central star being completely obscured.” Previous observations had been taken at radio wavelengths and hadn’t revealed how interesting it was.
Follow-up studies on GoHam revealed an estimated mass 2.5 times larger than the Sun. The mass of the disk is thought to be 0.03 solar masses, which sounds small until you realize that’s 20 times greater than every planet, asteroid, and comet in the Solar System combined. There are some signs a planet is already forming.
A Hubble image of Gomez’s Hamburger, starting off the meat-bun named class of side on stars
Image Credit: NASA/processed by Jud Schmidt CC by 2.0
Astronomers like to give similar objects thematically similar names – thus Mothra for the star that resembles one called Godzilla – so the new discovery called for something related to Gomez’s Hamburger. Noting what look like fangs extending from the northern side, the discoverers thought a reference to Dracula was appropriate. Co-author Dr Ana Mosquera is originally Uruguayan and the team adopted her suggestion to name it after her country’s national dish, a bun filled with beefsteak, cheese, ham, and various vegetables.
“Denser clumps collapse under gravity until fusion starts,” lead author Dr Ciprian Berghea of the US Naval Observatory told IFLScience. “The newborn star is in the so-called ‘pre-main sequence’ and is still surrounded by a dense disk of gas and dust and by an envelope, which is what is left of the cloud clump. If the envelope is very faint you can only see the brighter ‘edges’ of the envelope, the ‘fangs’. You could probably see more of the envelope with better observations.” To that end, the team is trying to get the Hubble or JWST to spend time on DraChi.
The announcement includes reference to other objects described as similar to the pair – but all are much smaller, either because of intrinsic size or greater distance, and therefore harder to study. Dracula’s Chivito or DraChi, appears 50 percent larger than GoHam, despite probably lying at a similar distance. The central star is suspected of being more than a third hotter than the Sun, while the mass of its disk is also thought to be a little lower than GoHam’s.
The paper has been submitted to the Astrophysical Journal Letters, and a preprint can be found on ArXiv.org.
[H/T ScienceAlert]
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